ARITHMETIC an
In multiplication, for which several processes are available, the product is obtained in some cases by separating the multipliers into factors and subsequently adding the partial products. In other cases a schematic process is introduced whose peculiarities are shown in the example 315-37 = 11 655.
SIS
The result of the multiplication is obtained by the addition of the figures found within the rectangle in the direction of the oblique lines. With regard to division we have only a few notices. Probably, however, complementary methods were not used.
The earliest writer giving us information on the arithmetic of the Arabs is Al Khowarazmi. The borrowing from Hindu arithmetic stands out very clearly. Six operations were taught. Addition and subtraction begin with the units of highest order, therefore on the left; halving begins on the right, doubling again on the left. Multiplication is effected by the process which the Hindus called Tatstha (it remains standing).* The partial products, beginning with the highest order in the multiplicand, are written above the corresponding figures of the latter and each figure
* Cantor, I., p. 674, 571.